Brief Description :
X-linked agammaglobulinemia (XLA; OMIM 300300) is an immunodeficiency caused by mutations in the gene coding for Bruton's tyrosine kinase (BTK). Patients with XLA have decreased number of mature B cells and lack of all immunoglobulin isotypes causing susceptibility to severe bacterial infections. Hereditary immunodeficiency-causing mutations are collected into ImmunoDeficiency mutation databases (IDbases) (1), which are available at http://bioinf.uta.fi/imt/bioinfo/. IDbases contain mutation data, both published and directly submitted information. For each patient the following information is given (when available): The identification of the entry and plain English description of the mutation are followed by reference and formal characterisation of the mutation. Last are the various parameters from the patient. IDbases are maintained with MUTbase program suite (2) which provides an easy, interactive and quality controlled submission of information to mutation databases. For further study of the databases on the World Wide Web, a number of tools are provided. The program package also writes and updates a large number of Web pages e.g. about distribution and statistics of disease-causing mutations, and changes in restriction patterns. The BTK is crucial for signalling in B cells. It belongs to the Tec family of cytoplasmic protein tyrosine kinases. The Tec family proteins consist of five distinct structural domains, which are from the N-terminus, a pleckstrin homology (PH) domain, a Tec homology (TH) domain, a Src homology 3 (SH3) domain, a SH2 domain, and the catalytic kinase domain. Mutations in all the five domains cause XLA. The structural consequences of the mutations have been studied based on crystallographic and NMR structures as well as computer-aided molecular modelling.